* Television flickers. The lines that make up the picture are refreshed 25 times per second and the whole screen flashes 50 times per second. Both sources of flicker can cause seizures.
-Wilkins, Darby, Stefanson, Jeavons and Harding. Television epilepsy: the role of pattern. Electroencephalography and clinical Neurophysiology.

* Flicker is not perceptible at frequencies of about 100 flashes per second, but it nevertheless affects firing of cells in the retina and subcortical structures.
-Berman, Greenhouse, Bailey, Clear, and Raasch. Human electroretinogram responses to video displays, fluorescent lighting and other high frequency sources.

* Heart rate is increased when fluorescent lighting flickers impercetibly.
-Watts and Wilkins. The role of provocative visual stimuli in agoraphobia.
Psychological Medicine.

Report 8/28

FOCUS:
"Does visual entertainment have an effect on the physical body?"